Inventive concepts relate to a semiconductor memory, and more particularly, to a nonvolatile memory device, an erase method thereof and a memory system including the same.
A storage device may store data under the control of a host device such as a computer, a smart phone and a smart pad. A storage device may include a device for storing data (e.g., a magnetic disk like a hard disk drive (HDD)) and/or a device for storing data in a semiconductor memory such as a solid state drive (SSD) and a memory card. The semiconductor memory may be a nonvolatile memory.
Examples of nonvolatile memory include a read only memory (ROM), a programmable ROM (PROM), an electrically programmable ROM (EPROM), an electrically erasable and programmable ROM (EEPROM), a flash memory, a phase change RAM (PRAM), a magnetic RAM (MRAM), a resistive RAM (RRAM), a ferroelectric RAM (FRAM), etc.
As semiconductor manufacturing technology develops, capacities in nonvolatile memory devices may increase. Increasing the capacity of a nonvolatile memory device may be accomplished by increasing the number of memory cells of the nonvolatile memory device and/or by increasing the number of bits being stored in the memory cells. In particular, in the case of increasing the number of bits being stored in the memory cells (e.g., bits per memory cell), a storage capacity of a semiconductor memory may increase without changing the size (or substantially changing the size) of the semiconductor memory. However, if the number of bits stored in the memory cell increases, an additional operation may be needed to program data in a memory cell or read data from a memory cell. As a result, an operation speed of the nonvolatile memory device may be reduced.